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488+638= white?

micheal rosen

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I understand that blue and yellow LED's mix together to make white, so does it stand to reason that a cyan wavelength and red wavelength combine to make white? I could see pass blue+green reflect red dichroic mirrors being used along with red and the newer cyan diodes to make relatively simple white lasers. But, they wouldn't be full color would they? could you make yellow? could you make green? blue is obviously out of the question.
 
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CurtisOliver

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Re: 488+538= white?

I take it you meant 638. :p
In theory you will get close to true white.
IIRC, white has been produced by mixing 589 with 488 before. It is all about balance.
But there wouldn't be much in the way of tuning with two lasers like there is with RGB.

Edit: See attached
 

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diachi

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Re: 488+538= white?

I take it you meant 638. :p
In theory you will get close to white.
IIRC, white has been produced by mixing 589 with 488 before. It is all about balance.
But there wouldn't be much in the way of tuning with two lasers like there is with RGB.
It does make white, of course you'll get different results based on your 488:638 ratio.

See below, 488nm + 632nm.



I've seen it done with 473nm and 589nm before too.
 

micheal rosen

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I take it you meant 638. :p
In theory you will get close to true white.
IIRC, white has been produced by mixing 589 with 488 before. It is all about balance.
But there wouldn't be much in the way of tuning with two lasers like there is with RGB.

Edit: See attached
Yes 638 indeed, I typed that way to quickly :crackup:. Vomit green and cyan would be an interesting combination but probably not white. Im suprised to hear that yellow and cyan would make white. It should be greenish shouldnt it?

It does make white, of course you'll get different results based on your 488:638 ratio.

See below, 488nm + 632nm.



I've seen it done with 473nm and 589nm before too.
Cool! This is pretty much exactly what i wanted to see. A white handheld laser isnt looking to far off now. Remember XPL lasers? the alibaba seller with handheld combined magenta and yellow lasers? I wonder if theyd be willing to put a red and cyan together for us :thinking:

Long time to see, good to see you come back.
Im glad im getting interested in lasers again too! seeing all the wonderful single modes popping up is awesome. I never really had an appreciation for single mode lasers till I got my first high power violet and realised how nearly perfect the beam was. I cant wait to get my hands on a 473, 488, and that 505! hoping for a 495 someday too. And I can only dream of the day we see the yellow-orange spectrum begin to fill up.
 

CurtisOliver

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It's good to see you on again. :)
I gathered. :p
Yep, it can produce white. Like Diachi has pointed out so can other combinations.
Balance is the key.
I too am after a <505 as well. 495nm is not far away I believe. One 505 iteration has hit 501nm. A bit more development on either side of the spectrum (480's and 505's) and we could see 495nm or there arounds.
As for yellow-orange diodes. We can only hope. It would take an hybrid approach of semiconductors to produce in that band. It used to be either red or blue/violet. But now we are seeing red, orange-red and orange with one and light-blue, cyan, aquamarine and green with the other. The gap is decreasing over time. :)
 

Encap

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I understand that blue and yellow LED's mix together to make white, so does it stand to reason that a cyan wavelength and red wavelength combine to make white? I could see pass blue+green reflect red dichroic mirrors being used along with red and the newer cyan diodes to make relatively simple white lasers. But, they wouldn't be full color would they? could you make yellow? could you make green? blue is obviously out of the question.
Welcome back--long time no see. LPF needs returning members along with good new ones----so many noobs, trolls, and spammers recently --is a breath of fresh air to see a returning member
+rep when I can

You can mix wavelengths to get various visual color effects but they do not create any new wavelengths nor conventional full spectrum "white"---white created still remains the wavelengths used-- if you split the created "white" apart with a prism you get the wavelengths used to create the illusion of white.

Keep in mind--Color is not a physical property; it is merely the brain’s interpretation of different wavelengths of light. Color names are words/symbols for that brain activity.

I don't think there is any chance XPL will do anything other than what they do--the mass produce low quality lasers and their combining lasers are pretty poor quality examples--flawless combining of 2 beams each with the exact same divergence and so on is not easy to do--is a complicated manipulation of things-- more so the closer you get to ideal--especially in a hand held is probably not really possible other than OK/good enough for whatever purpose.

Very close but not perfect is the low cost mini RGB module 400mW for $399 from OPTLasers see: https://optlasers.com/en/28-rgb-modules

ArticDude made a nice hand held out of the OPTLAsers module that pretty well. See: https://laserpointerforums.com/f44/arctic-s-open-source-rgb-laser-host-99595.html

You can see the different colors he gets in his photography here: https://laserpointerforums.com/f48/enchanted-beams-thread-98105.html
 
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ZRaffleticket

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Can confirm with the 485 and 635 I have, though my ratio is a bit too heavy on the red and it's a bit pink when they're combined
 

paul1598419

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I've been trying to buy an RGB white module with driver from Laserlands, but for some reason, I have now been banned from buying from them. Sent a few messages, but no replies. I was planning on using the TTL inputs to vary the output using a 10 KHz square wave and PWM it to get a good variation on all three colors. Don't know how I ended up on their ban list. I remember Chris saying he ended up there too. If it doesn't happen, I'll wait until the same unit shows up on someone else's site.
 
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Benm

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Can confirm with the 485 and 635 I have, though my ratio is a bit too heavy on the red and it's a bit pink when they're combined
If mixed in the right ratio these should be fairly white, but probably not -exactly- white.

If you look at gamut diagrams a line from 485 to 635 almost goes thrue pure white, but it misses it by a small bit. So it will be a bit pink or a bit cyan depending on the ratio.

These are technicalities though, if you get the ratio right i'd think the averag person would answer 'white' if you ask them what color that beam is. What technically is white, and what people consider white are different things. You see this with color temperature of broad spectrum light too: some like 2700K warm white, most people would consider 3500-4000K 'just white' and some prefer higher color temperatures to be 'cold white' like on xenon car headlights that are actually blueish. And yes i know the relationship between what people consider 'warm' white is opposite of the actual color temperature, but that's just how things are ;)
 

Benm

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That looks about right on the gamut chart - but do notice how small the actual 'white' area is.

People will percieve it as 'white light' though unless they have some reference to directly compare it too.

It's just a thing we generally do - a white van will look white both to your eyes and on a photograph even when it is taken in sunny conditions. If you actually measure the color of that van in a digitized image it is far from 'white' in the sense that RG and B intensities are equal.
 

paul1598419

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Got the RGB module and driver for $46.00 on Laserland's website. It has three separate TTL inputs, so I am planning on building a 10 KHz square wave generator that has modulation of the pulse width on three channels so I should be able to incrementally control the colors on all three lasers. It will, of course be +5 volts P-P.
 

micheal rosen

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Welcome back--long time no see. LPF needs returning members along with good new ones----so many noobs, trolls, and spammers recently --is a breath of fresh air to see a returning member
+rep when I can

You can mix wavelengths to get various visual color effects but they do not create any new wavelengths nor conventional full spectrum "white"---white created still remains the wavelengths used-- if you split the created "white" apart with a prism you get the wavelengths used to create the illusion of white.

Keep in mind--Color is not a physical property; it is merely the brain’s interpretation of different wavelengths of light. Color names are words/symbols for that brain activity.

I don't think there is any chance XPL will do anything other than what they do--the mass produce low quality lasers and their combining lasers are pretty poor quality examples--flawless combining of 2 beams each with the exact same divergence and so on is not easy to do--is a complicated manipulation of things-- more so the closer you get to ideal--especially in a hand held is probably not really possible other than OK/good enough for whatever purpose.

Very close but not perfect is the low cost mini RGB module 400mW for $399 from OPTLasers see: https://optlasers.com/en/28-rgb-modules

ArticDude made a nice hand held out of the OPTLAsers module that pretty well. See: https://laserpointerforums.com/f44/arctic-s-open-source-rgb-laser-host-99595.html
Well, if the purpose is to make a laser that looks white, and has a white beam, I think that cyan+red would make for a very cheap alternative. Much less than $400, and also less complicated (in the case that you are not buying a prebuilt module).

Can confirm with the 485 and 635 I have, though my ratio is a bit too heavy on the red and it's a bit pink when they're combined
Interesting! how does the beam look? Id imagine its far closer to blue/green than the spot, considering how shorter wavelengths are scattered much more.

Like Benm said, with the right ratio it can get close!

Interesting. I Didn't know that the color gamut could work like that! definitely a difficult thing to perfect.

I fear that getting a white beam is going to be quite difficult knowing how little red scatters.

Also: does anyone know if pass green+blue reflect red dichros work well with cyan wavelengths?
 
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diachi

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Interesting! how does the beam look? Id imagine its far closer to blue/green than the spot, considering how shorter wavelengths are scattered much more.


I fear that getting a white beam is going to be quite difficult knowing how little red scatters.
The spot and the beam are going to be the same colour. The scattering effect is only going to apply over very long distances.

You can adjust your 488:638 ratio to get the right colour, it's not going to be perfectly white but it'll be close, just need to play around with it.
 

Encap

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Well, if the purpose is to make a laser that looks white, and has a white beam, I think that cyan+red would make for a very cheap alternative. Much less than $400, and also less complicated (in the case that you are not buying a prebuilt module)
White just going to be visual cortex created visual illusion based on your particular eyes and their response to light. Seeing cyan is a mix of responses from blue and green come cells response and then you add input from red sensing cone cells and you get a RGB artificially created illusion of white. 288nm + 638 is still going to be just that + the problem of making both beam and dot align perfectly plus tewaking the output level until you feel you see an acceptable white and so on. Not cheap to do and will not make a good nand held.
As mentioned--"keep in mind--color is not a physical property; it is merely the brain’s interpretation of different wavelengths of light. Color names are words/symbols for that brain activity."

If you want a created white illusion that you can look at until bored to tears with it---that low cost $49 RGB module mentioned above is a good way to go.
Depends upon your purpose/intended use and so on.
 
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